When articles require operations using power/machine tools such as circular saws, routers, drill presses and the like, it is desirable to be able to position a workpiece rapidly, accurately, and repeatably in relation to an operative member of a power/machine tool or the like. Various methods are employed to do this with the amount of time required to setup for that being amortised over the number of parts requiring the particular operation e.g. cutting, drilling or whatever. The greater the speed, convenience and accuracy with which a setup can be established and used, the more efficiency is achieved. The more this efficiency can be applied to a lesser number of articles requiring such operations, as is the case when doing very small production runs and in situations requiring constant changes in setup, the improvement in efficiency becomes increasingly more significant.
A problem with setting up a worklength stop to an accurate length occurs in quickly locating the appropriate position with repeatable accuracy; this is often done simply by measuring between the stopping member and the operative member of the power/machine tool, normally requiring a test cut and then usually needing readjustment, with the whole process being repeated with each subsequent setting. A part solution to this is sometimes achieved by fixing a measuring tape to the workpiece support with time consuming regard to the accurate location of the tape and requiring great care that the tape's end does not interfere with the operative member. This works adequately for a cutting machine while the same angle of cut is used, but when changing from say a 90.degree. square cut to, for example, 45.degree. mitre, the previous setting is of no value and is in danger of enmeshing the tape with the operative member of the power/machine tool, and so another time consuming setup is required each time this is done.
Further, it is generally more desirable to use a worklength stop on a flat work piece support to provide constant support for sometimes flexible materials that require the operation; but when doing so, there is often a problem with a build up of debris at the stopping member; this can cause inaccuracies and also considerable inconvenience in having to watch for that effect and by the constant need to interrupt the work to clear the debris. A device that is substantially self clearing of such debris would provide considerably increased efficiency.
Furthermore, it would be advantageous if a worklength stop could be adapted for accurately spacing trenches, grooves and holes in relation to an operative member of a power/machine tool and therefore each other on a workpiece.
The present invention is concerned with a distance locating device of the form of device 80 shown in FIGS. 11-13 of PCT/AU88/00499, but in a preferred form has the added benefit of being adapted to act as a work length stop and barb without reorientation as required for the bar 90 as shown between FIGS. 13 and 14 of PCT/AU88/00499.